The present invention relates to the field of electronic signal processing, and more particularly to a method and an apparatus for characterizing the unknown state of a physical system having a time varying history, the characterization being made with reference to a known state of like physical systems.
For many physical systems the ability to predict accurately the future state of the system is as important as, and in some instances more important than, knowledge of the present state of the system. For example, in the field of medical science the ability to predict future medical problems of seemingly healthy individuals is of paramount importance. Although this ability is extremely desirable, such predictions based on presently known techniques are often inaccurate.
Illustrative of this problem is the current limited ability to predict from early symptoms the onset of coronary problems in the future in a seemingly normal individual who presently exhibits a negative electrocardiographic reading and who as no prior history of heart disease or problems typically associated therewith. Currently, techniques exist for analyzing electrocardiographic data. For example, an article by Teichholz et al., 35 The American Journal of Cardiology 531-36 (April 1975), entitled "The Omni Cardiogram, New Approach To Detection Of Heart Disease In Patients With A Normal Resting Cardiogram", discusses a technique for analyzing and detecting subtle degrees of abnormality not apparent in raw electrocardiographic data. Although the analytical technique described in this article possesses certain desirable attributes and results in a better understanding of the underlying data, it still has certain drawbacks and limitations. More specifically, it does not enable one to predict accurately and quantitatively the future onset of coronary disease in a patient possessing an apparently normal electrocardiogram. It is believed that prior to the present invention this problem has gone unsolved.
Accordingly, it is a general object of the present invention to overcome the drawbacks and limitations of known signal processing systems for characterizing the state of a physical system when it is unknown.
It is a specific object of the present invention to provide a method and an apparatus for evaluating the present state and/or predicting the future state of a physical system.
It is another object of the present invention to provide a method and an apparatus for characterizing the state of a medical system with reference to a known state of like systems.